Siegel, the screenwriter of last year’s surprise knockout The Wrestler, steps up to the directing chair for this even bleaker drama, which he also wrote and set amid the fringes of another sports arena: the fans of sports talk radio. Were it not for his dark dramatic tones, à la Seventies films such as Fat City, Siegel might replace Ron Shelton as the go-to guy for sports-related movies. Big Fan, however, sticks to its guns and gives in to none of the sappiness or redemptive qualities of The Wrestler. The big fan of the title is Paul Aufiero (Oswalt), a pudgy parking-garage attendant in his mid-30s who lives with his mother and has no apparent passion for anything but football’s New York Giants. He’s an anonymous schlub who gains a sense of celebrity every night when he’s recognized as “Paul from Staten Island,” a regular, wee-hours caller of the Sports Dog radio talk show. He and his only friend Sal (Corrigan), who basks in Paul’s “celebrity,” tailgate every Giants game and know no other topic of conversation than their team. One night while out eating a slice of pizza, they spot their idol, Giants quarterback Quantrell Bishop (Hamm), and surreptitiously follow him to a strip club in Manhattan, where all hell breaks loose once they finally encounter their hero. Up until this point, Big Fan is a searing and focused character study but, as with The Wrestler, the development of narrative intrigue is not Siegel’s forte. Members of Paul’s family badger him to improve his lifestyle but mostly come off as broad caricatures. Paul also faces a moral dilemma, although he fails to really grasp its magnitude. Thus the film begins to sputter and lurch toward a conclusion that leaves the protagonist in exactly the same mental space he was at the beginning. Even though the character’s lack of growth or improved insight is frustrating as a viewer, there’s something admirable about Siegel’s dogged resistance to altering Paul’s worldview. One thing Siegel got absolutely right in this film is the casting. Oswalt, who is better known as a comedian, seems a perfect fit for Siegel’s single-minded loser. Indie regular Corrigan hits a perfect note of dim adulation, while fast-talking Rapaport is just the right guy to play Paul’s call-in nemesis, “Philadelphia Phil.” Big Fan, in the end, doesn’t exactly sail through the goalposts, but the film puts up a valiant show nevertheless.